Power tool



| F. KOTT 7 POWER TOOL Q Dec. 28, 1948.

2 Sheets-Sheet 1 Filed Jan. 21, 1946 'INVENTOR.

-LEO FJKOTT' ATTORNEY- F. Ko'r'i' 2,457,565

POWER TOOL Dec 2 8, 1948.

2 Sheets-Sheet 2 Filed Jan. 21, 1946 I :ll 42 35 H6 6 as 44 34 INVENTOR. LEO F. KOTT Patented Dec. 28, 1948 POWER TOOL Leo Kott; Detroit; Mich; Appneatiomnnuary 21, 194c;..seriar1sio. srasee This invention: relates generally to: powerv tools and refers more particularlyto power tools of the'type-employed informing: holes in hardsubstances such, for exampleesrock; concrete or similar materials by imparting a succession of blows on the work engaging implement.

One of the-objects of. thisiinventionis. to provide a tool= havingimeans-iiorv successively, moving an implement into engagement with thework to be operated upon at a rapid rate to produce a succession: of blows or impacts on the. work. and having means for rotatingthe implement during engagement ofthe latter with theworko Thus, by using an implement inthe-form of a drill; a combined cutting and pounding. action is. obtained. This action. greatly facilitates forming holes-in hard substances of-thegeneraltype stated and the flutes of. the drill or. implement. enable readily removing thepulverizedparticles of the substance. resulting, from the above action.

A further object. ofthis-iinvent'ionisitd effectively cool. the working. parts of" the tool b'y elmployingmeans responsive "to the rapid motionor the tool on its operative stroke tororee a-b1ast of air adjacent the the greatestheat. v I

Another object ofTtliis. inventionis to provide a light weight-portable tOoYembod'yirlg the above features and'composed of'a' relatively few Simple parts capable of being. inexpensively manufactured and assembled.-

The foregoing. as well as'other' objects Will. be made more apparent as this description proceeds, especially when considered. in connection with the accompanying'drawing's, wherein? Figure 1 is a longitudinal sectional view through a power'tool embodying the features of this. invention;

Figure 2 is a View similar to" Figure" 1"sl1'owin'g certain of the parts in elevation? Figure 3'is an" end"elevational'view ofthe 'tool;

Figure 4 isa cross sectionalviewtaken substantially on the planeind icate'd bytl'ie l'ine 4-4- of Figure 1;

Figure 5 is-a prospective -view of apartofthe tool shown in- Figure "1 Figure 6 is a fragmentary! elevationailiview, partly in section, of the: lower-end: portioni'o'f; the tool;

Figure 7 is 'a fragmentary.elevationaliview; partly: in section, ofthedrive: gear embodied-in the tool; and

Figure8-is an enlarged? elvational View of a cam follower embodied'in thet ool;

Referring now. more inidetailitothe drawings,

parts. ofi'tlie tool"subjecte'd to an annular shoulder formed in the'bore-33.

having an annular groove-in 'sleeve30; An annular. seal. 34

itwwillbe noted that-the" power tooli's provided with a casing [5 comprising two axially aligned sections l6 and IL The section It is threaded into the section II and cooperates with the lat ter to formlani enlarged chamber I 8 intermediate the ends ofthecasingr- A- bevel gear I9 is supported in the chamber 18 for rotation about'the axis-of the casing and is adapted' tomesh with a bevelled pinion 2'0.v The-pinion 2b is secured to a driveshaft 2 and thelatter is journalled. in a projecting portion 22 of the casing section- II by a ball bearing. 231 The projecting portion 22'; may form a, handle for the tool and the-shaft 2| may be connected directly to a suitableprime mover (not shown herein).

The-front side of the pinion. [9' and the adj'a cent-wall 24 of the chamber l8 are formed with registering. annular grooves concentrically arrangedwith respect. to the'axis ofthe ca'sihgClB and adapted to rotatably sup-port ahpluralit'y. of ball'sZSl The rear side of the pinion l9" is counterbored to. receive an. annular ring 26" suitably secured in anannular recess formed in therear wa1l 21 -of. the chamber I'8I' The adjacent surf-aces of the pinion l 9 andring 26' are: formed -with-reg istering. annular grooves for receiving. a series of; balls 28; The balls Z'Bcooperatewith the balls toprovide-anti-frictionthrustbearingsfor; the pinion I9. l v

A- hub- 25 is provided at-thefront side of the pinion l9 and is internally threaded for threadably receiving. the rear endof a-sleeve-30. The front end o-f the-sleeve is formed-with aradially outwardly extending annular enlargement 3 the periphery for rotatably supporting a series of balls 32-, The balls 32 engage the inner surface of the bore- 33 formed in-the casingsection 16- and provide an anti-friction support for the front endoi the ofresilientmaterial-,- such-for eXample as rubber-or synthetic rubber ismounted on the sleeve-3 0 at the rear side ottheenlargement 3lfor engagement with-the inner" surfaceof the bore 33;;

Ah adapter 3-5 is supported in the bore 33"at the: front-side ofthe enlargement- 31 on the sleeve 3ll-and is formed-with a radially outwardly extending annular flange intermediate the ends thereof. The flange 36 assumes aposltion betweenthe enlargement 3t on the sleeve and The front-side of the adapter 'is formed with a threaded bore for threadably engagin the rear and 05a tool holding chuck- 392 v The; chuck has a-taperedbore 40 ion receivingthecorres end of the section 11 suitable packing material 51 is confined between inner surface of the sleeve :abuts the plug 53. be provided with It follows from the above .is yieldably urged into contact with the adaptor "35 by the coil spring ger by the coil spring of the sleeve 30. Thus, rotation of the sleeve by the pinion 19 effects a corresponding rotation of the adaptor and tool holding chuck 39.

The rear end of the bore 45 in the casing section 11 is closed by a cap 41 having axially spaced plates 48 and 49. The front plate 49 engages the rear end of the bore 45 and therear plate 48 is detachably secured to the adjacent by fastener elements 50. A

the plates and is adapted'to engage the inner surface of the bore 46 to prevent the escape of lubricant from the bore. The grip 41 is provided with a threaded bore 52 for threadably engaging a plug 53 and the rear end of the cap is formed with a tubular guide 54.

A plunger 55 is slidably mounted in the casing between the adaptor 35 and the cap 41. The :rear end of the plunger telescopically engages the tubular guide 54 and is provided with a radially outwardly extending annular flange 56. The

periphery of the flange 5s slidably engages the inner surface of the bore 46 and effectively supports the rear end of the plunger. The front endof the plunger is formed with a radially outwardly extending enlargement 51 and the periphery of this enlargement slidably engages the 30 to support the front end of the plunger. A coil spring 58 is supported in the casing 15 between the plunger 55 and the plug 53. As shown particularly in :Figure 1 of the drawings, the front end portion of thecoil spring 58 extends into a bore 59 in the rear end of the coil spring If desired, the plug 53 may a projection 60 which extends axially into the coil spring to stabilize the rear end portion of the latter.

plunger 55 and the that the plunger 55 58. Movement of the plun- 58 is controlled by a cam In the present instance,

5! and a follower 62.

the cam extends spirally around the periphery ot" the plunger latter and is formed integral therewith. The follower 62 is rotatably supported in a radially extending bore 63 formed 55 intermediate the ends of the in the pinion l9;and the radially inner end of the follower engages the cam 6|. The plunger 55 is prevented from rotation with the pinion 19 by a pin'64 rotatably supported in a radial bore 65 formed in the casing section 11 and having the inner end engaging in an axially elongated slot 66 formed in the periphery of the plunger 55. Thus, rotation of the pinion 19 relative to the plunger 55 effects a movement of the follower 62 along the cam 61. As shown in Figure 5 of the drawings the cam 61 extends spirally around the plunger for substantially 360. The angle of the spiral or helix is predetermined so that as the pinion l9 approaches one complete revolution, the plunger 55 is moved to its rearwardmost position against the action of the spring 58. As the pinion I9 conthreadably .forwardmost position by the sleeve 30,so that communicates with the bore in itsadjustedposition by means .of a spring clip 68 'secured'zto'thecap 41 in frictional engagement with the plug. When the plunger is moved to its by the spring 58, the follower 52 assumes a position adjacent the low or 'f-orwardmost point 69 of the cam, sothat continued rotation of the pinion retracts the plunger 55 and compresses the spring 58.

. 1The impact or blow applied to the adaptor 35 by theplunger 55 is transmitted directly to the implement or drill 42 and is applied to the work by the drill. At the same time, the drill is rotated the work being operated upon is simultaneously subjected to the impact force and to a cutting action. As a result, holes may be readily formed'in exteremelyhard materials such, for example, as rock, concrete and stone, 4 v i In order to reduce friction andwear of the parts to a minimum, the follower 52isrotatably supported in the bore 53. As shown particularly in Figure 8 of the drawings, the follower is formed with axially spaced enlargements 19 having annular grooves in'the peripheral surfaces thereof for vreciprocably receiving a series of balls 11. The balls 11 engage the inner surface of the bore 53 and provide an anti-friction bearing for the follower. The radially outer end of the follower is formed with a cap 12 seated on a shoulder at the radially outer end of the bore and is provided with a spherical tip 13 which abuts a strip 14. The strip, 14 extends across the. radially outer end of the bore 63 and is secured to the pinion 19.

Thus, the minimum resistance is offered to rotation of thefollower 62, and wear of the latter is substantially reduced. The pin 54 is ofsimilar construction and is rotatably supported in a hardened sleeve 14 forming a liner for the bore 55. The pin 64 is held inassembled relationship by means of a plug 15 threaded in the radially'outer end ofthe bore 65. f

Upon reference to Figure '2' ofthe drawings, it will be noted that the chamber lfllcommunicates with the atmosphere through ports 15 and also 46 in advance of the enlargement 55 on the plunger through passages 11. Thus, air is drawn into and exhausted from the interiorv of the casin 15 upon reciprocation of the enlargement 56 with the plunger 55. This has a cooling effect on. the various .parts ,of the tool and contributes ,rnaterially to maintaining theseparts below critical temperatures. A port 18 is'provided in thebore 46 for equalizing the pressure in the bore to the rear of the piston during operation of the tool.

,What- I claim as my invention is: I

1. In a power tool, a tool holden'means for imparting a succession of blows'to said holder including a reciprocable plunger, a spring constantly urging said plunger in a direction toward said tool holder, means'for intermittently urgin the plunger in the opposite direction, said means including a cam on the plunger, a member rotatable about the axis of the plunger, a follower rotatable with said member "and engageable with said cam,

and a driving connection between the member and tool holder permitting sliding movement of the latter relative to the former.

2. In a power tool, a tool holder, means for imparting a succession of blows to said holder including a reciprocable plunger, a spring constantly urging said plunger in a direction toward said tool holder, means for intermittently urging the plunger in the opposite direction, said means ineluding a cam on the periphery of the plunger, a member rotatable about the axis of the plunger and having a follower engageable with the cam, means for rotating said member, and a driving connection between the member and tool holder permitting sliding movement of the latter relative to the former.

3. In a power tool, a casing, a plunger mounted for reciprocation within said casing, a gear journalled in the casing and bored to receive the plunger, a cam on the periphery of the plunger extending generally spirally around the axis of the plunger, and a follower rotatably supported in a radial bore in said gear and engageable with said cam.

4. In a power tool, a casing, a tool holder at one end of the casing, a plunger mounted for reciprocation within the casing and having a longitudinally extending groove in the periphery, a pin supported by the casing for rotation and engageable in the groove to hold the plunger against rotation, a spring constantly urging the plunger in a direction toward the tool holder, means for intermittently urging the plunger in the opposite direction, said means including a gear journalled in the casing and bored to receive the plunger, a cam on the periphery of the plunger extending generally spirally around the axis of said plunger, a follower rotatably supported in a radially extending bore in said gear and engageable with the cam, and means for rotating the gear.

5. In a power tool, a casing, a tool holder at one end of the casing, a plunger mounted for reciprocation within the casin and having a longitudinally extending groove in the periphery, a pin supported by the casing for rotation and engageable in the groove to hold the plunger against rotation, a spring constantly urging the plunger in a direction toward the tool holder, means for intermittently urging the plunger in the opposite direction, said means including a gear journalled in the casing and bored to receive the plunger, a cam on the peripher of the plunger extending generally spirally around the axis of said plunger, a follower rotatably supported in a radially extending bore in said gear and engageable with the cam, means for rotating the gear, and a driving connection between the gear and tool holder permitting sliding movement of the latter relative to the former.

LEO F. KOTT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

